The following invention relates to a high voltage regulator for the anode voltage supply of a CRT which is powered by a deflection flyback pulse generator.
The anode voltage supply for a color CRT, which is usually on the order of 20,000 volts, is maintained by utilizing the high voltage pulse output of a deflection flyback pulse generator and developing a DC voltage from these pulses by using a high voltage transformer and a large storage capacitor. Variations in brightness of the screen, however, can alter the voltage of the power supply, and this in turn can cause a change in the actual screen dimensions (horizontal and vertical). For example, if the data signal calls for a very bright screen, the beam current goes up which can deplete the anode voltage supply. The electron beam can then be deflected with less energy so the screen tends to become larger. One could reduce the deflection voltage to reduce the horizontal scan but that would only effect the horizontal dimension.
In the past, anode voltage supplies powered by the deflection flyback pulse generator have either been unregulated, or a separate regulated power supply has been used for the anode voltage which was not powered by the deflection flyback pulse generator. The use of two separate power supplies is obviously more costly and consumes more space within the chassis. A desirable feature would therefore be a voltage regulator for compensating the flyback deflection pulse generator for voltage drops caused by variations in anode beam current without the requirement for a separate power supply.